History and technology background

In 1946 Léon Theremin invented an espionage tool for the Soviet Union which retransmitted incident radio waves with audio information. Sound waves vibrated a diaphragm which slightly altered the shape of the resonator, which modulated the reflected radio frequency. Even though this device was a covert listening device, not an identification tag, it is considered to be a predecessor of RFID technology, because it was likewise passive, being energized and activated by electromagnetic waves from an outside source.^[2]

Similar technology, such as the IFF transponder invented in the United Kingdom in 1915, was routinely used by the allies in World War II to identify aircraft as friend or foe. Transponders are still used by most powered aircraft to this day. Another early work exploring RFID is the landmark 1948 paper by Harry Stockman, titled "Communication by Means of Reflected Power" (Proceedings of the IRE, pp 1196–1204, October 1948). Stockman predicted that "... considerable research and development work has to be done before the remaining basic problems in reflected-power communication are solved, and before the field of useful applications is explored."

Mario Cardullo's U.S. Patent 3,713,148 in 1973 was the first true ancestor of modern RFID; a passive radio transponder with memory. The initial device was passive, powered by the interrogating signal, and was demonstrated in 1971 to the New York Port Authority and other potential users and consisted of a transponder with 16 bit memory for use as a toll device. The basic Cardullo patent covers the use of RF, sound and light as transmission media. The original business plan presented to investors in 1969 showed uses in transportation (automotive vehicle identification, automatic toll system, electronic license plate, electronic manifest, vehicle routing, vehicle performance monitoring), banking (electronic check book, electronic credit card), security (personnel identification, automatic gates, surveillance) and medical (identification, patient history).

A very early demonstration of reflected power (modulated backscatter) RFID tags, both passive and semi-passive, was performed by Steven Depp, Alfred Koelle, and Robert Freyman at the Los Alamos National Laboratory in 1973^[3]. The portable system operated at 915 MHz and used 12-bit tags. This technique is used by the majority of today's UHFID and microwave RFID tags.

The first patent to be associated with the abbreviation RFID was granted to Charles Walton in 1983 U.S. Patent 4,384,288.

The largest deployment of active RFID is the US Department of Defense use of Savi ^[4] active tags on every one of its more than a million shipping containers that travel outside of the continental United States (CONUS). The largest passive RFID deployment is the Defense Logistics Agency (DLA) deployment across 72 facilities implemented by ODIN ^[5] who also performed the global roll-out for Airbus ^[6] consisting of 13 projects across the globe

RFID 101

RFID 101

Radio Frequency Identification (RFID) refers to technologies that utilize radio waves to automatically identify individual items. When RFID first emerged, it was used in tracking and access applications. Since then, it has developed as a robust technology with ever increasing processing speeds, wider reading ranges, and larger memory capacities.

How RFID Works RFID technology allows information to be collected quickly and automatically and does not require contact or line-of-sight. The reader generates an electromagnetic field through its antenna. Once the tag enters the detection area, it becomes active when receiving a signal through its own antenna. This signal is used to turn on the tag's transmitter and allows the tag to communicate and exchange information with the reader. The reader then transmits the data to a computer or server for processing and management. A basic system consists of two components including a tag and a reader with an antenna. Tag RFID tags vary in shape and size and are either active or passive. Active RFID tags are powered by an internal battery and are commonly read/write, which allows the tag's data to be modified or rewritten. The memory size of an active tag varies depending on the application requirements. Passive RFID tags like our Health Link implantable microchip, on the other hand, are not powered by a battery, but instead rely on power generated by the reader. The read range for active tags ranges from a few inches to over a hundred feet. The read range for passive tags ranges from one to ten feet. Reader The reader is a handheld or fixed-mount device that emits electromagnetic (radio) waves. These waves can range from one inch to 100 feet and are dependent on power output and the radio frequency used. Frequency RFID systems can run on frequencies anywhere between 30 KHz to 500 KHz (low frequency), 850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz (both considered high frequency). Systems that run on low frequency are less costly and have shorter reading ranges. Our patient identification microchip and systems like asset tracking typically use low frequency. High frequency systems are more costly, have faster reading speed, and have longer reading ranges. RFID systems used in automated toll collection are of this system type.